Bacteriology in burn patients undergoing mechanical ventilation

Anti-Pseudomonas aeruginosa Vaccines and Therapies: An Assessment of Clinical Trials

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes high morbidity and mortality in cystic fibrosis (CF) and immunocompromised patients, including patients with ventilator-associated pneumonia (VAP), severely burned patients, and patients with surgical wounds. Due to the intrinsic and extrinsic antibiotic resistance mechanisms, the ability to produce several cell-associated and extracellular virulence factors, and the capacity to adapt to several environmental conditions, eradicating P. aeruginosa within infected patients is difficult. Pseudomonas aeruginosa is one of the six multi-drug-resistant pathogens (ESKAPE) considered by the World Health Organization (WHO) as an entire group for which the development of novel antibiotics is urgently needed. In the United States (US) and within the last several years, P. aeruginosa caused 27% of deaths and approximately USD 767 million annually in health-care costs. Several P. aeruginosa therapies, including new antimicrobial agents, derivatives of existing antibiotics, novel antimicrobial agents such as bacteriophages and their chelators, potential vaccines targeting specific virulence factors, and immunotherapies have been developed. Within the last 2-3 decades, the efficacy of these different treatments was tested in clinical and preclinical trials. Despite these trials, no P. aeruginosa treatment is currently approved or available. In this review, we examined several of these clinicals, specifically those designed to combat P. aeruginosa infections in CF patients, patients with P. aeruginosa VAP, and P. aeruginosa-infected burn patients.

The Effects of Glutamine Supplementation on Reducing Mortality and Morbidity among Burn Patients: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Glutamine (GLN) has been proven to improve the prognosis of severely burned patients. GLN supplementation in critical illness has gained extreme popularity among researchers over the years, and its safety and efficacy are still under question. Therefore, we aim to study the role of GLN supplements in decreasing mortality, length of hospitalization (LOH), and infection in severely burned patients. PRISMA guidelines were used to design and conduct this systematic review. MEDLINE, Cochrane, and EMBASE databases were used to search for randomized controlled trials (RCTs) in January 2022. In order to assist in the search, MeSH terms such as burn injury, GLN, and RCT were used. As a result of reviewing the literature, 1112 publications were found. We included only 7 RCTs after implanting our inclusion criteria. There were 328 patients enrolled in the study, with 166 patients (50.61%) were allocated to GLN supplementation and 162 patients in the control groups (49.39%). The risk of infection was significantly lower among patients who received GLN supplementation than those in the control groups (RR = 0.41, 95% CI, 0.18 to 0.92, p = 0.030). The risk of death was significantly lower among GLN-receiving patients compared to non-GLN-receiving patients (RR = 0.09, 95% CI, 0.01 to 0.63, p = 0.016). GLN supplementation has been linked to lower hospital mortality and infection-related morbidity in burn patients. Furthermore, larger-scale and higher-quality studies are needed to assess whether there are any statistically and clinically significant changes.

Enteral glutamine supplementation reducing infectious morbidity in burns patients: a randomised controlled trial

PURPOSE

Enteral glutamine supplements have been shown to reduce infectious morbidity in trauma patients, but their effect on patients with burns is not completely studied. The objective of this study was to measure the impact of enteral glutamine supplementation on infectious morbidity and in turn, the hospital-stay in patients with burns.

METHODS

Thirty patients with burns were randomly divided into two groups with 15 patients in each, the study (glutamine supplemented) and control group. Patients were randomised to receive either isonitrogenous mixture without glutamine or isonitrogenous mixture with glutamine until complete healing of the burn wound occurred. Incidence of positive blood culture, wound culture, total leucocyte count, hospital-stay and mortality was recorded.

RESULTS

The results showed that the incidence of positive blood culture was considerably reduced in the study group (0.20±0.41) vs. control (0.73±0.96; p = 0.065). The incidence of positive wound culture was significantly reduced in the study group (1.00 ± 1.25) vs. control (3.53 ± 2.47; p = 0.001). In addition, the wound healing was better and hospital-stay days were reduced in the study group (22.73 ± 9.13 days) vs. (39.73 ± 18.27 days; p = 0.003).

CONCLUSIONS

These results indicate that enteral glutamine supplementation in adult burn patients could abate the degree of infectious morbidity and reduce hospital-stay.

Analysis of anaerobic blood cultures in burned patients

The utility of anaerobic blood culturing is often debated in the general population, but there is limited data on the modern incidence, microbiology, and utility of obtaining routine anaerobic blood cultures for burned patients. We performed a retrospective review of the burned patients electronic medical records database for all blood cultures drawn between January 1997 and September 2005. We assessed blood cultures for positivity, organisms identified, and growth in aerobic or anaerobic media. 85,103 blood culture sets were drawn, with 4059 sets from burned patients. Three hundred and forty-five single species events (619 total blood culture isolates) were noted in 240 burned patients. For burned patients, four isolates were obligate anaerobic bacteria (all Propionibacterium acnes). Anaerobic versus aerobic culture growth was recorded in 310 of 619 (50.1%) burned patient blood culture sets. 46 (13.5%) of the identified organisms, most of which were not obligate anaerobic bacteria, were identified from solely anaerobic media. The results of our study suggest that the detection of significant anaerobic bacteremia in burned patients is very rare and that anaerobic bottles are not needed in this population for that indication. However anaerobic blood cultures systems are also able to detect facultative and obligate aerobic bacteria; therefore, the deletion of the anaerobic culture medium may have deleterious clinical impact.

Lésions respiratoires et brûlures

INTRODUCTION

Smoke inhalation and respiratory complications are still the major causes of mortality in severely burned patients.

STATE OF THE ART

The diagnosis is suspected clinically on the basis of history and physical examination and can be confirmed bronchoscopically. Respiratory failure in burned patients occurs through a number of associated mechanisms. Pneumonitis and adult respiratory distress syndrome (ARDS) are common early complications. New pulmonary treatments and advances in ventilation have reduced the incidence of both barotrauma and infectious complications. Tracheal stenosis can occur as a late complication of prolonged mechanical ventilation.

PERSPECTIVES

Clinical and experimental studies have shown that damage to the mucosal barrier and the release of inflammatory mediators are the most important pathophysiological events following smoke inhalation. Manipulation of the inflammatory response following inhalation may be a treatment option in the distant future.

CONCLUSION

Inhalation injury occurring in burned patients can produce severe respiratory and systemic complications.

Decreased mortality and infectious morbidity in adult burn patients given enteral glutamine supplements: A prospective, controlled, randomized clinical trial*

OBJECTIVE

Enteral glutamine supplements have been shown to reduce infectious morbidity in trauma patients, but their effect on burn patients is not known. The objective of this study was to measure the impact of enteral glutamine supplementation on infectious morbidity, length of care, and the immune system in burn patients.

DESIGN

Double-blinded, randomized clinical trial.

SETTING

Burn center.

PATIENTS

Forty-five adults with severe burns.

INTERVENTIONS

Patients were randomized to receive either glutamine or an isonitrogenous control mixture until complete healing occurred. Length of care, incidence of positive blood culture, and mortality were recorded. Phagocytosis by circulating polymorphonuclear cells was measured every 3 days.

MEASUREMENTS AND MAIN RESULTS

Patient characteristics were similar in both groups. Four patients were excluded from the analysis, because three of them died within 72 hrs and the fourth could not receive enteral nutrition and amino acid supplements for the first 10 days. Of the remaining 41 patients, length of care in the survivors was not different between groups (0.9 vs. 1.0 days/percent total body surface area for glutamine vs. control, respectively), positive blood culture was three times more frequent in control than in glutamine treatment (4.3 vs. 1.2 days/patient, p <.05), and Pseudomonas aeruginosa was detected in six patients on control and zero on glutamine (p <.05). Phagocytosis by polymorphonuclear cells was not different between groups. Mortality rate was significantly lower in glutamine than in control: intention to treat, two vs. 12 (p <.05); per protocol analysis, zero vs. eight (p <.01).

CONCLUSIONS

Enteral glutamine supplementation in adult burn patients reduces blood infection by a factor of three, prevents bacteremia with P. aeruginosa, and may decrease mortality rate. It has no effect on level of consciousness and does not appear to influence phagocytosis by circulating polymorphonuclear cells.